Photos and video I took during an August 2014 south Greenland maintenance tour of promice.org climate stations and an extreme ice survey time lapse camera went viral, featuring a surprisingly (to me and others) dark surface of Greenland ice.

What we know, the southern Greenland ice sheet hit record low reflectivity in the period of satellite observations since 2000 due to a ~2 month drought affecting south Greenland…

map with colors indicating when record low albedo was observed. The photos are from the blue patch near the southern tip of Greenland.

Snowfall summer 2014 for south Greenland would have kept the melt rates down by brightening up the surface. Summer 2014, at the PROMICE.org QAS_A site, we recorded ice loss from the surface at a place we thought was above equilibrium line altitude, where the surface would lose no ice in an ‘average climate’. The higher than normal melt rates allowed the impurities to concentrate near the surface in a process documented for snow surfaces by Doherty et al. (2013).

To avoid misinterpretation, black carbon is only part of the darkness, the rest is dust and microbes (See Dumont et al. 2014 and Benning et al. 2014). The photos are from the lowest part of the ice sheet’s elevation. The upper elevations do not get nearly this dark. This satellite image illustrates for west Greenland how dark the surface gets, down to 30% reflectivity.

Sky selfie

Our colleague Jason Box of the Geological Survey of Denmark and Greenland (GEUS), and graduate student Johnny Ryan of Aberystwyth University spent much of the summer on the western ice sheet at Camp Dark Snow, near Kangerlugssuaq on the Arctic Circle (67 degrees north latitude at 1,010 meters above sea level). The team was investigating the Greenland surface albedo, climate, and surface melting, and how these evolve during summer. As part of the research, they have been using drones (Unmanned Aerial Vehicles, or UAVs) to photograph the surface from low altitude to examine the development of surface structures associated with melting. Strips of images and albedo measurements from the UAV are compared with simultaneous satellite images from the NASA MODIS sensor as an intermediate state to relate ground albedo measurements with that of the entire ice sheet. UAV photos reveal a surface riven with fractures, and drained by ephemeral rivers of melt water. The mid-summer melt surface in this area is pocked with 0.5 to 1 meter-wide (1.5 to 3 feet-wide) potholes with black grit and dust collected at the bottom. This black material is called cryoconite, and is comprised of dust and soot deposited on the surface, and melted out from the older ice exposed by melting. The dark patches are often glued together by tiny microbes.

Images of the Greenland Ice Sheet near Kangerlugssuaq in west-central Greenland taken by a drone (UAV) used to evaluate the evolving albedo of the ice sheet surface during the summer melt season. At top left, Prof. Jason Box and Johnny Ryan, a Ph.D. student at Aberystwyth University, hold the drone they used. Top left, the drone takes a picture of the surface (and the operator, J. Ryan) on August 9, 2014 from low altitude, showing numerous cryoconite holes filled with black dust, grit, and soot that had accumulated in the winter snowpack, and melted out of the older ice below. Bottom, a higher-altitude image of the same area reveals sinuous melt streams and linear fractures, as well as small speckles of cryoconite holes on the ice sheet. Tents from the camp are also visible as colorful dots against the ice surface.

ps. Professors Alun Hubbard and Niel Snooke at Aberystwyth University deserve a lot of credit for the UAV development.

For almost two months we endured (and let’s face it, enjoyed) camp life at its fullest; sleeping on the ice every night, falling into countless water filled holes, enduring the discomforts of cold-numbed toes and keeping up with the seemingly endless treadmill of camp maintenance… But at the end of the day, it was these guys, the “Ice Algae”, that were the true stars of the show!

Algal cells as seen through the field microscope. Examples of individual cells have been highlighted with a green circle.

The picture above is an image of what we see when we look down the microscope at our surface ice samples. Dark-coloured ice algae clearly dominate the sample. Typically we estimated that there were tens of thousands of algal cells in every milliliter of sample. When you bulk these samples up to liters and gallons, and then to the volume of surface ice found within biologically active area of the Greenland Ice Sheet (currently estimated at >400,000 km2), we’re looking at some serious cell numbers. As Marek Stibal explained previously, these guys are packed with a dark purple-brown pigment that protects them from sunlight, but also causes the darkening of the ice surface.

So, were we pleased with our field season? Definitely! Once we had figured out the best way to interpret the environment, we set about to amass as much data as we could, so that any conclusions that are drawn are as robust as possible. Overall we took around 600 samples for biological analysis, over 2000 close range spectral readings and, most amazingly, we individually counted around 94,000 algal cells in the field. This, on top of keeping a well-oiled camp going, kept us more than busy over the summer.

Hard at work in the science tent: Marek Stibal making microscope slides, Jason Box processing data and Karen Cameron taking a break from counting cells!

Now that we are back from our field work, our next mission is to interpret just how much albedo change is due to the darkening effect of algal growth on the ice surface, and furthermore, how much this darkening is contributing towards ice melt. In addition, we also intend to use laboratory analyses in Copenhagen to look into some of the more intricate components of the surface ice ecology that we have been living alongside all summer.

Camp Dark Snow spanned the 2014 Greenland melt season, with 59 days camping, 17 June to 14 August. We had very few logistical snags and our science objectives were met. We had strings of clear sky days, followed by rain, sometimes heavy, to evaluate the time evolution of ice reflectivity.

We managed 26 UAV missions that fill the intermediate scale between our point measurements and that from satellite. Marek delivered a heavy box of ice samples to Copenhagen. On camp for most days, Karen developed a regular 2 day routine that has delivered for example 2,262 spectral reflectance point measurements as part of 29 surveys. The count of microbiological cell counts is staggering.

Coptering over moulins produced some video useful in communicating a video we call “follow the water” I presented at the AGU in 2013 and that will appear soon as a from Peter Sinclair. Several videos are in production to be shared in coming days, weeks, months.

We’re atop a heap of data and we’re busy beginning the next phase of the campaign; digestion.

A 21-23 September mile marker for us will be the International Workshop on “Quantifying Albedo Feedbacks and their Role in the Mass Balance of the Arctic Terrestrial Cryosphere” at the University of Bristol, UK. Organisers: Martyn Tranter and Martin Sharp. The meeting is supported by the International Arctic Science Committee.

Arrived yesterday to Kangerlussuaq, west Greenland, now 6 AM, we’re just about out the door in effort to put more numbers on how fire and other factors are affecting Greenland’s reflectivity as part of the Dark Snow Project.

Premier climate video blogger Peter Sinclair is a key component of the Dark Snow Project because of our focus on communicating our science to the global audience. The video below was shot and edited last night quickly as we prepare for a return to our camp a few hours from now.

The video does not comment on the important issue of carbon. So, here’s a quick research wrap-up… Wildfire is a source of carbon dioxide, methane and black carbon to the atmosphere. Jacobson (2014) find that sourcing to be underestimated in earlier work. Graven et al. (2013) find northern forests absorbing and releasing more carbon by respiration due to Arctic warming’s effects on forest composition change. At the global scale, the land environment produces a net sink of carbon, taking up some 10% of the atmospheric carbon emissions due to fossil fuel combustion (IPCC, 2007). Yet, whether northern wildfire is becoming an important source of atmospheric carbon (whether from CO2 or CH4 methane) remains under investigation. University of Wisconsin-Madison researchers find:

“fires shift the carbon balance in multiple ways. Burning organic matter quickly releases large amounts of carbon dioxide. After a fire, loss of the forest canopy can allow more sun to reach and warm the ground, which may speed decomposition and carbon dioxide emission from the soil. If the soil warms enough to melt underlying permafrost, even more stored carbon may be unleashed.

“Historically, scientists believe the boreal forest has acted as a carbon sink, absorbing more atmospheric carbon dioxide than it releases, Gower says. Their model now suggests that, over recent decades, the forest has become a smaller sink and may actually be shifting toward becoming a carbon source.

“The soil is the major source, the plants are the major sink, and how those two interplay over the life of a stand really determines whether the boreal forest is a sink or a source of carbon

Boreal forests like those in the Northwest Territories are burning at rates “unprecedented” in the past 10,000 years according to the authors of a study put out last year. The northern reaches of the globe are warming at twice the rate as areas closer to the equator, and those hotter conditions are contributing to more widespread burns.

The Intergovernmental Panel on Climate Change’s landmark climate report released earlier this year indicates that for every 1.8°F rise in temperatures, wildfire activity is expected to double.

We have a team on Greenland ice right now, and until mid August, tasked with measuring the impact of dark particles on ice melt. We are asking for support to increase our abilities to detect smoke landing on Greenland ice. The support will help us afford expanding our laboratory work.

High up in the Himalaya, it lurks. It is hard to spot with the naked eye. Yet we see the damage it leaves in its wake. No, this is not the elusive Himalayan yeti (though I do have camera traps set out). Rather, I am referring to black carbon or soot – resulting from incomplete combustion of fossil fuels, as well as biofuels and biomass – which deposits on snow and ice in the Himalaya. These dark particles absorb sunlight, warming snow and ice, leading to faster glacier mass loss. These particles are smaller than a strand of hair. Small but mighty, so it seems. Yet, black carbon isn’t the only culprit. Locally and regionally derived dust also can impact snow melt. While dust is a natural occurrence on the planet, recent land use changes, such as road and trail construction can add to the amount. Thus, it is important to consider the combined effect of soot and dust.

As in the Arctic, dark particles on Himalayan snow are a concern as they lead to enhanced heating, melting and sublimation. While melting ice on Greenland can directly contribute to sea level increases, in the Himalaya ice loss affects people on a more local and regional scale – by disrupting water resources, as well as cutting off climbing routes. The Nepalese Himalaya are home to eight of the world’s 8000-meter peaks. As climate continues to change and conditions become more treacherous for climbing, this may affect the local communities who rely on trekkers and mountaineers for income.

Smog visible from Everest base camp, April 2014.

From October 2013 – end of May 2014, my team and I collected snow samples across the Khumbu valley in the Everest region (eastern part of Nepal), including Island Peak, Lobuche East, Khumbu glacier, Ngozumpa glacier, Cho La and Renjo La. In central Nepal, we collected samples from Annapurna South and Mt. Himlung in the remote NarPhu valley, on the border with Tibet. Out in the field, the technique is straight-forward: wash your hands (or ice axe) in the snow first, then collect a gallon-size bag of snow from the top few centimeters and the subsurface. The former represents dry deposition from the air while the latter represents deposition in the last snowfall event. You then quickly come back down to camp to melt the samples and run the water through filters, capturing pollutants and other contaminants, which later are analyzed in the lab. The technique I am using was developed by Dr. Carl Schmitt at the National Center for Atmospheric Research, with whom I am collaborating (http://www2.ucar.edu/atmosnews/just-published/8856/measuring-pollutants-andean-glaciers). He developed this while working with the American Climber Science Program throughout the Cordillera Blanca in Peru (http://climberscience.wordpress.com).

Sampling snow at 20,150 ft. on Lobuche East, Khumbu valley, Nepal.

Preliminary results show a dominance in relative mass concentration of dust in samples, with particularly high levels of black carbon/dust in more frequented regions such as the high mountain passes and climbing peak high camps. Whodunit? Well, that’s more complicated, but a few suspects are in custody:

dust from eroding trails at the lower altitudes, due to frequent human and animal traffic during the high trekking seasons in the autumn and spring

black carbon from wildfires

soot from yak dung burning stoves in local villages

dust from road construction in Kathmandu

black carbon from diesel-belching buses and trucks

soot from brick factories, though farther geographically, may be carried to the mountains by the wind.

It is clear we are dealing with anthropogenic changes and that needs to be addressed at the local and national government levels. Understanding the sources better and developing mitigation efforts where possible will be key, as well as understanding the effects on the water supply in the region in order to facilitate adaptation.

Acknowledgments Funding for my work includes: National Science Foundation (NSF); USAID; the US Fulbright Program; Geological Society of America (GSA); the Explorers Club; National Snow and Ice Data Center’s (NSIDC) CHARIS project; Rice Space Institute; and individual sponsors/donors through the University of Colorado Boulder and crowd-funding from Petrishdish.org and Rockethub.com.

The NASA MODIS sensor on the Terra satellite provides surface reflectivity data since early 2000 enabling us to evaluate just how dark Greenland ice is today and in comparison with the past 14 years.

The data show that 2014 ice sheet reflectivity (also called albedo) has been near record low much of 2014, especially at the highest elevations.

15 years of albedo data for the uppermost region of the ice sheet

The darkness of the surface at high elevations is consistent with the findings of Dumont et al. (2014) that an increasing dust concentration on the ice sheet in the pre-melt season from decreasing snow cover on land upwind of the ice sheet may be a significant darkening factor.

If there will be a persistent pattern of warm air brought over the ice sheet as in 2012, we should expect melting at the ice sheet upper elevations. Why? Low reflectivity heats the snow more than normal, removing more of the ‘cold content’. A dark snow cover will thus melt earlier and more intensely. A positive feedback exists for snow in which once melting begins, the surface gets yet darker due to increased liquid water content, increased snow grain size, and possible other factors such as microbial growth.

For the ice sheet as a whole, low reflectivity in 2014 has been exceeded only by years 2012, 2013, and 2011, depending on the time of year…

15 years of albedo data for the entire ice sheet and peripheral glaciers

The Greenland reflectivity anomaly map features red and orange colors that indicate a relatively dark surface near the end of June especially at the low elevations where most melting occurs.